Zinc metal reacts with hcl as follows: zn + 2 hcl ⇒ zncl2 + h2 what mass of zinc metal is needed to produce 600.0 ml of hydrogen gas collected over water at 30.0°c and at 775 mmhg?

it is required a mass of Zn equal to m= 1.608 gr of Zn

Explanation:

Assuming that the hydrogen behaves as an ideal gas ( in reality it has positive deviations from the gas law, but we can neglect the small correction) , then

P*V=n*R*T

n = P*V/(R*T)

where

P= absolute pressure = 775 mmHg = 1.02 atm

T= absolute temperature = 30°C+273 = 303 K

V= volume = 600 mL = 0.6 L

R = ideal gas constant = 0.082 atm*L/(mol*K)

n = number of moles of H₂ gas

replacing values

n = P*V/(R*T) = 1.02 atm*0.6 L/(0.082 atm*L/(mol*K)*303 K) = 0.0246 moles of H₂

from the reaction

Zn + 2 HCl ⇒ ZnCl2 + H2

since 1 mole of H2 requires 1 mole of Zn to react , then

m = nz * M

where

nz = number  of moles of zinc =  number of moles of H₂ gas  = 0.0246 moles

M = molecular weight of zinc = 65.38 gr/mol

m = mass of zinc required

therefore

m= 0.0246 moles * 65.38 gr/mol = 1.608 gr of Zn

m= 1.608 gr of Zn

what is the question?

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.